1. Field of the Invention
The present invention is related to a microstrip meander-line antenna, and more particularly, to a multi-band microstrip meander-line antenna for a wireless communication system.
2. Description of the Prior Art
With rapid development in wireless communication technology, portable electronic devices, such as mobile phones, notebook computers or personal digital assistants (PDAs), can receive and transmit wireless signals using built-in antennas. When connected to WWAN (wireless wide area network) for data transfer, the user of these portable devices can surf the Internet or check personal emails.
A well-designed antenna can enhance the efficiency, sensitivity and reliability of the wireless communication system. Currently, there are three main types of antennas used in a mobile communication system: patch antennas, ceramic antennas, and microstrip meander-line antenna. The patch antenna has narrow bandwidth and low transmission efficiency. The ceramic antenna is expensive and its specific absorption rate (SAR) has not yet qualified current electromagnetic regulations. The microstrip meander-line antenna has wider bandwidth (>10%) and can be integrated into circuit boards without extra welding procedures, thereby capable of reducing manufacturing costs.
On the other hand, the operating frequency of different wireless communication system may vary. For example, the operating frequency of a Wi-Fi (Wireless Fidelity) system is around 2.4 GHz-2.4835 GHz and 4.9 GHz-5.875 GHz; the operating frequency of a WiMAX (Worldwide Interoperability for Microwave Access) system is around 2.3 GHz-2.69 GHz, 3.3 GHz-3.8 GHz and 5.25 GHz-5.85 GHz; the operating frequency of a WCDMA (Wideband Code Division Multiple Access) system is around 1850 MHz-2025 MHz; the operating frequency of a GSM (Global System for Mobile communications) 1900 system is around 1850 MHz-1990 MHz. In the ideal case, multiple frequency bands can be provided using a single antenna, so that the user can conveniently access various wireless communication systems. Also, the size of the antenna should be as small as possible, especially when used in portable electronic devices.